The present invention relates to the inclusion of a lipid-enriched hydrophobic lotion on the body facing material of disposable absorbent articles, such as diapers, training pants, adult incontinence products, underpants, and feminine care products and the like. More particularly, the present invention relates to improving skin health via enhancement of skin barrier function by the delivery of lipid and non-lipid materials from the body facing material of disposable absorbent articles to the skin.
The stratum corneum is the outer-most layer of the skin and is responsible for regulating skin water levels and functioning as a barrier against chemicals and other stressors found in the environment. The complex arrangement of lipids in the intercellular space of the stratum corneum is responsible for the establishment of normal barrier function. Multi-layered structures of cholesterol, ceramides, and fatty acids, as well as some other minor lipids, provides the major barrier to the transport of hydrophillic substances into the or through the skin. The link between the barrier function and skin health is apparent from the skin inflammation caused by lipid extraction from the skin.
Skin barrier can be damaged due to a number of mechanisms. Physical abrasion, for example caused by the repeated rubbing of abrasive materials, such as absorbent tissues or wipes, on the skin, strips away layers of the skin and thus damages skin barrier. Biological fluids, such as urine, feces and vaginal secretions, may contain a variety of components that can damage skin barrier. Examples of these components include proteases, lipases and bile acids. Once the skin barrier is compromised, these components, in addition to other constituents of biological fluids, can initiate or exacerbate skin inflammation.
Diaper dermatitis, for example, is a genre of skin conditions that, in large part, originate from impaired barrier function. Impairment of the skin barrier can result from a variety of factors, including; increased skin hydration due to the occlusion of the skin caused by diapers, enzymatic skin damage due to fecal and urinary enzymes, and physical damage caused by repeated cleaning of the skin with cloths or wet wipes.
Excessive hydration also has a negative impact on skin barrier. The hydration level of diapered skin, for example, may reach between five to ten times that of undiapered skin. Frequent contact of diapered skin with urine may also contribute to increased skin hydration. Increased skin hydration disrupts skin lipid organization in the stratum corneum. This disruption may increase the skin permeability of irritants from feces and urine, thus increasing the risk of skin inflammation.
Diapered skin is normally cleansed several times a day with wipes utilizing solutions containing surfactants. The surfactants can extract lipids from the stratum corneum or disorganize the lipid structure within the stratum corneum, thereby decreasing the barrier function. The wipe material can cause physical damage to the skin and thus lead to decreased barrier function.
Disposable absorbent articles such as diapers, training pants, adult incontinence products, absorbent under pants, and feminine care products have been used to absorb body fluids and leave the skin dry. Disposable absorbent articles of this type generally comprise a liquid impermeable back sheet member, an absorbent core or assembly, and a liquid permeable body facing material. It is the body facing material that comes into contact with the wearer""s skin. While the body facing material is made of a soft compliant material, it can abrade the skin during use and may not leave the skin completely dry and free of the bodily fluids, such as solid or semi-solid waste, the absorbent article is trying to absorb. During frequent insults of bodily fluids and frequent use of disposable absorbent articles, the skin can become so abraded as to appear red and be sore to the touch.
Typically, barrier creams, lotions or ointments are used to provide an artificial hydrophobic barrier on the skin and treat skin conditions such as diaper rash. The application of these chemistries to the skin is often messy and inconvenient. They are typically used only when signs of diaper rash are apparent.
Diaper liners may be treated with emollients, such as petrolatum, that can be transferred to the skin through normal diapering practices. Once transferred to the skin, diaper liner formulations may provide an artificial barrier against feces and urine. These formulations may require high concentrations of petrolatum to ensure sufficient transfer to the skin for a health benefit. High concentrations of petrolatum can be messy, greasy to the touch, and may impair the fluid handling properties of an absorbent article, such as a diaper. The slow penetration of petrolatum into the skin can lead to smearing of the agent over the skin and onto clothes and other materials.
Thus, what is needed in the art is:
Topical chemistry delivered from a bodyside material of an absorbent article that protects, maintains, and/or recovers skin barrier against irritants in biological fluids.
Topical chemistry delivered from a bodyside material of an absorbent article that absorbs into the skin, is non-greasy and cosmetically acceptable to the consumer.
Topical chemistry delivered from a bodyside material of absorbent article that does not impair the waste containment functions of the diaper.
It has been discovered that superior skin barrier enhancing disposable absorbent articles can be made using a skin barrier enhancing, oil based-hydrophobic composition comprising from about 0.1 to about 95 weight percent natural fats or oils, from about 0.1 to about 10 weight percentxe2x80x94sterols and sterol derivatives, from about 0.5 to about 20 weight percent of humectant, from about 1 to about 20 weight percent of water-in-oil emulsifying surfactant/surfactant combination having an HLB range from about 3 to about 6, from about 5 to about 95 weight percent emollient, from about 5 to about 95 weight percent wax, and from about 1 to about 25 weight percent viscosity enhancer. The composition may have a melting point from about 30xc2x0 C. to about 100xc2x0 C. and a process viscosity of greater than about 50 centipoise. Also, the composition may have a penetration hardness of from about 5 millimeters to 360 millimeters.
Hence, in one aspect, the present invention is a skin barrier enhancing disposable absorbent article that can be made applying, on the outer surface of the body facing material, a melted lipid-enriched hydrophobic composition comprising an emollient, a wax, a viscosity enhancer, a humectant, a water-in-oil emulsifying surfactant having an HLB range from about 3 to about 6, a sterol and sterol derivative, and a natural fat or oil, and thereafter resolidifying the composition to form a distribution on the outer surface of the body facing material. Because the composition is a solid at room temperature and rapidly solidifies after application, it has less tendency to penetrate and migrate into the body facing material. Compared to body facing materials treated with liquid formulations, this leaves a greater percentage of the added solid lotion composition on the surface of the body facing material where it can contact and transfer to the user""s skin to provide enhanced skin health benefits. Furthermore, a lower add-on amount can be used to deliver the same benefit at a lower cost because of the efficient placement of the composition substantially at the surface of the body facing material of the absorbent articles.
In another aspect, the present invention is a body facing material wherein the outer surface of the material has solidified deposits of an oil based-hydrophobic composition comprising from about 0.1 to about 95 weight percent natural fats or oils, from about 0.1 to about 10 weight percent sterols and sterol derivatives, from about 0.5 to about 20 weight percent of humectant, from about 1 to about 20 weight percent of water-in-oil emulsifying surfactant/surfactant combination having an HLB range from about 3 to about 6, from about 5 to about 95 weight percent emollient, from about 5 to about 95 weight percent wax, and from about 1 to about 25 weight percent viscosity enhancer. The composition may have a melting/freezing point of from about 30xc2x0 C. to about 100xc2x0 C. and a process viscosity of greater than about 50 centipoise. Also, the composition may have a penetration hardness from about 5 millimeters of penetration to 360 millimeters of penetration.
In another aspect, the present invention resides in a method of treating a body facing material with a composition by comprising: (a) a natural fat or oil, a sterols and sterol combinations, humectant, a water-in-oil emulsifying surfactant(s) having an HBL range from about 3 to about 6, an emollient, a wax, and a viscosity enhancer, to a temperature above the melting point of the composition, causing the composition to melt; (b) uniformly applying the melted composition to the outer surface of the body facing material; and (c) resolidifying the melted composition. The composition may have a melting point ranging from about 30xc2x0 C. to about 100xc2x0 C.